Question

Possible Duplicate:
Is Java pass by reference?

I need to modify the content of a variable that is passed to a function within that function.

The type is String. I want to inject a preceeding char when using the insertString function of an extendeded class of PlainDocument.

Answer 1

Use a wrapper class:

public class Wrapper
{
    public String text;
}

// ...

public static void changeString(Wrapper w, String newText)
{
    w.text = newText;
}

You can use it like:

Wrapper w = new Wrapper();
w.text = "old text";
changeString(w, "new text");
System.out.print(w.text);

OUTPUT:

new text

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Also see this answer: https://stackoverflow.com/a/9404727/597657